Re: [Caml-list] using modules to wrap c++ classes

[Joel Reymont <joelr1@gmail.com>]

So I ended up with something like this

--- Callbacks.ml

type t

type 'a callback =
  | Alert of ('a -> Alert.t -> unit)
  | AskQuote of ('a -> Ask.t -> unit)
  | BestAskQuote of ('a -> Ask.t -> unit)
  | BidQuote of ('a -> Bid.t -> unit)
  | BestBidQuote of ('a -> Bid.t -> unit)
  | ClosePrice of ('a -> ClosePrice.t -> unit)
  | ClosingIndicator of ('a -> ClosingIndicator.t -> unit)
  | EndQuote of of ('a -> EndQuote.t -> unit)
  | EquityOptionList of of ('a -> EquityOptionList.t -> unit)
  | EquityOptionStrategyList of of ('a -> EquityOptionStrategyList.t -> unit)
  | HighPrice of ('a -> HighPrice.t -> unit)
  | Indicator of ('a -> Indicator.t -> unit)
  | IndicatorReplay of ('a -> IndicatorReplay.t -> unit)
  | LimitOrderBook of ('a -> LimitOrderBook.t -> unit)
  | LowPrice of ('a -> LowPrice.t -> unit)
  | MarketMode of ('a -> MarketMode.t -> unit)
  | OpenPrice of ('a -> OpenPrice.t -> unit)
  ...

external make : unit -> t = "Callbacks_new"
external set : t -> 'a callback -> unit = "Callbacks_set"

I now want to grab the closure from the constructor on the C side and
stick it into a callback array. Is this sufficient?

extern "C" CAMLprim value
Callbacks_set(value v)
{
  CAMLparam1(v);
  int i = Tag_val(v);
  CAMLlocal1(f);
  f = Field(0, v);
  caml_register_global_root(f);
  callbacks[i] = f;
  CAMLreturn(Val_unit);
}

    Thanks, Joel



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